Small power generating device and water faucet device

ABSTRACT

A small generator includes a hydraulic turbine provided in a fluid path rotating with a passage of a fluid in a predetermined flow and a rotator coupled to the hydraulic turbine rotating together with the hydraulic turbine which acts as a rotor portion opposed to a stator portion having multiple layers in a stepping motor including the stator portion, wherein the rotor portion relatively rotates with respect to the stator portion with the passage of the fluid, thereby generating a power.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to a small generator utilizing ahydroelectric generated by a water flow passing through a faucet and aWater tap apparatus contains a small generator is provided.

2. Related Art

Conventionally, there is widely provided an automatic Water Tapapparatus contains a sensor sensing that a hand held out beneath afaucet. Then the faucet starts to flow water from is on the basis of thesensor sensing. In recent years, moreover, there is proposed anapparatus such that a small generator is provided in a fluid path ofsuch an automatic Water Tap apparatus and a power generated by the smallgenerator is storaged to complement for the power consumption of acircuit such as the sensor as shown in Japanese Utility ModelPublication Hei. 2-65775.

The structure of the small generator will be briefly described below. Ahydraulic turbine is provided in a fluid path to be a water flowing pathand rotates by receiving the hydroelectric of flowing water. A rotor isfixed integrally with the rotary shaft of the hydraulic turbine. Theouter peripheral surface of the rotor is a magnetized as a rotor magnet.The rotor magnet is opposed to a stator pole through the wall of anon-magnetic member. Moreover, single layer stator coil is provided tobe interlinked with a magnetic flux passing through the stator pole.Then, the hydraulic turbine rotates by receiving the hydroelectric ofthe flowing water so that a magnet rotates relatively with respect tothe stator pole. Therefore, the flow of the magnetic flux flowing to therotor and the stator pole is changed. As a result, a current flows tothe stator coil in such a direction as to prevent the change in the flowof the magnetic flux. After the current is rectified, it is stored in astorage battery.

As described above, the magnetic flux flows between the rotor and thestator pole in the generator. The magnetic flux acts as a resistancewhen the hydraulic turbine is to be rotated by the hydroelectric causedby flowing the water. In other words, a magnetic flux generated betweenthe rotor and the stator pole acts as a detent torque to brake theoperation of the hydraulic turbine during the starting and rotation ofthe hydraulic turbine. Accordingly, in order to rotate the hydraulicturbine, it should receive a flow amount and a hydraulic pressure beyonda predetermined value. Therefore, if the flow amount is small or thehydraulic pressure of the flowing water received by the hydraulicturbine is low, the hydraulic turbine is neither rotated nor generates apower. If the magnetic force of the rotor magnet is low, the detenttorque is reduced so that the hydraulic turbine itself is rotatedConsequently, an induced voltage generated during the rotation of therotor is also dropped so that the amount of power generation isextremely increased. In order to obtain a desirable amount of powergeneration, it is necessary to increase the magnetic force of the rotormagnetic to some extent and to maintain the flow and hydraulic pressureof a fluid for rotating the hydraulic turbine to some extent.

Under such circumstances, in the small generator for the automatic WaterTap apparatus which has been used widely, if the flow is specificallyset to 3 liters/minute or less, the detent torque acts as a resistanceso that the hydraulic turbine cannot be smoothly rotated. In order torotate the hydraulic turbine, it is necessary to set the flow more than3 liters/minute.

Water saving has been demanded for a long time in respect of theimprovement of the environment and other various problems. Under suchcircumstances, there has been a problem in that the amount of water toflow at a time should be reduced as much as possible also in theautomatic Water Tap apparatus. In addition, in the present situations inwhich a user's critical mind for water saving has been enhanced, thehydraulic pressure of the water discharged with the flow should also bereduced. It is necessary to give such an image that the water saving isbeing carried out through a drop in the hydraulic pressure.

SUMMARY OF INVENTION

It is an object of the invention to provide a small generator capable ofrotating a water turbine with a small flow to generate a sufficientamount of power and a Water Tap apparatus.

In consideration of the above-mentioned problems, according to an aspectto the present invention there is provided a small generator comprisinga hydraulic turbine, provided in a fluid path, rotating by passing afluid in a predetermined flow rate, a rotator, coupled to the hydraulicturbine, rotating together with the hydraulic turbine, the rotatoracting as a rotor portion opposed to a stator portion having multiplelayers in a stepping motor including the stator portion, wherein therotor portion rotates relatively with respect to the stator portion bywith passing the fluid to generate a power. Thus, the stator portion ofthe stepping motor for power generation is constituted by multiple oflayers. Therefore, each layer acts to cancel a detent torque between thestator portion and the rotor so that the detent torque can be reduced.As a result, the hydraulic turbine can rotate with a small flow at a lowhydraulic pressure.

According to another aspect of the present invention, in addition to theaspect of the present invention described above, a detent torquegenerated between the stator portion and the rotor is set to becancelled by the layers each other. For example, the detent torque ispositively set to be reduced by skewing each layer (rotating the layerin a circumferential direction to intentionally shift a pole thereof) orproviding a non-magnetic member between the layers. Consequently, thefunctions can be obtained more effectively.

Moreover, according to another aspect of the present invention, there isprovided a small generator comprising a hydraulic turbine, provided in afluid path, rotating by passing a fluid in a predetermined flow rate, arotator, coupled to the hydraulic turbine, rotating together with thehydraulic turbine, the rotator acting as a rotor portion opposed to astator portion having a plurality of coil portions in a brushless motorincluding the stator portion, wherein the rotor portion rotatesrelatively with respect to the stator portion by passing the fluid togenerate a power. Thus, the rotator coupled to the hydraulic turbineserves as the rotor portion opposed to the stator portion of thebrushless motor. Therefore, it is possible to reduce the detent torquethan that in a conventional generator of a conventional single layertype stepping motor. As a result, it is possible to rotate the hydraulicturbine with a small flow at a low hydraulic pressure.

According to another aspect of the present invention, in addition to theaspect to the present invention described above, a relationship betweenthe number of poles magnetized onto the rotor portion and the number ofcoil portions of the stator portion is set to 2-3, 4-3 or 4-6.Consequently, it is possible to further reduce the detent torque betweenthe stator portion and the rotor portion.

According to another aspect of the present invention, in addition to theaspect of the present invention, there is provided an injecting memberincluding an injecting hole which acts as a part of the fluid path andacts to throttle a flow for a passage to inject a fluid onto a bladeportion of the hydraulic turbine. Consequently, it is possible to raisea hydraulic pressure to some extent through the injecting hole even ifthe flow is small. Therefore, it is possible to rotate the hydraulicturbine more smoothly, thereby generating a power. Moreover, each of thesmall generators can generate a power with a small flow at a lowpressure by reducing the detent torque. Therefore, it is also possibleto generate a power without greatly raising the hydraulic pressurethrough an increase in the diameter of the injecting hole. In the casein which such setting is carried out, it is possible to reduce apossibility that the injecting member might be damaged due to a highhydraulic pressure.

Furthermore, according to another aspect of the present invention, thereis provided a Water Tap apparatus wherein a valve opening degree iscontrolled to include at least two modes of a water saving mode in whicha flow of a fluid to flow to a fluid path and a normal mode for a normalflow and the small generator of the present invention described inclaims 6 to 9 is provided in the fluid path. As described above, thedetent torque is reduced in the small generator according to the presentinvention described in claims 6 to 9 which is provided in the fluidpath. Therefore, it is possible to generate a power with a small flow ata low hydraulic pressure. Therefore, if the hydraulic pressure of thefluid to be supplied to the hydraulic turbine is set to be low, it ispossible to reduce a possibility that the member might be damaged due toa high hydraulic pressure in the normal mode and to sufficientlygenerate a power also in the water saving mode.

According to a seventh aspect of the present invention, in addition tothe sixth aspect of the present invention, the flow in the water savingmode is set to 2.0 liters/minute to 3.0 liters/minute. Therefore, thewater saving can fully be carried out and the power can be generated ina small amount of water.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a longitudinal sectional view showing a small generator of atwo-layer stepping motor type according to a first embodiment of theinvention;

FIG. 2 is a side view showing the small generator of FIG. 1 taken alongan arrow II in FIG. 1;

FIG. 3 is a bottom view showing the state of FIG. 2 taken along an arrowIII,

FIG. 4 is a typical view showing the relationship between a member(nozzle ring) for spraying a fluid onto a hydraulic turbine in a statein which a hydraulic pressure is raised by throttling a fluid path andthe hydraulic turbine,

FIG. 5 is a longitudinal sectional view showing a small generator of abrushless motor type according to a second embodiment of the invention,and

FIG. 6 is a side view showing the small generator of FIG. 5 taken alongan arrow VI in FIG. 5.

FIG. 7(a) is a sectional side view of the water tap apparatus containingthe small generator of the present invention;

FIG. 7(b) is a front sectional view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Each embodiment of a small generator and a Water Tap apparatus accordingto the invention will be described below in detail with reference to thedrawings.

First Embodiment

Primary, a small generator utilizing a two-layer stepping motor typeaccording to a first embodiment of the invention will be described withreference to FIGS. 1 to 4. FIG. 1 is a longitudinal sectional viewshowing a small generator of a two-layer stepping motor type accordingto the first embodiment of the invention. Moreover, FIG. 2 is a sideview showing the small generator of FIG. 1 taken along an arrow II inFIG. 1. Furthermore, FIG. 3 is a bottom view showing the state of FIG. 2taken along an arrow III. Moreover, FIG. 4 is a typical view showing arelationship between a member (nozzle ring) for spraying a fluid onto ahydraulic turbine in a state in which a hydraulic pressure is raised bythrottling a fluid path and the hydraulic turbine.

As shown in FIG. 1, the small generator utilizing a two-layer steppingmotor type according to the first embodiment comprises a casing 1, anozzle ring 2 provided in the casing 1, a hydraulic turbine 3 rotatablyprovided on the inner peripheral side of the nozzle ring 2, a rotor 4rotating integrally with the hydraulic turbine 3, a cup-shaped member 5formed of stainless which is provided on the outer peripheral side ofthe rotor 4, and a stator portion 6 of a stepping motor which is furtherprovided on the outside of the cup-shaped member 5.

As shown in FIGS. 1 and 2, the casing 1 includes a body portion 11, andan inlet path 12 and an outlet path 13 which are protruded toward theoutside of the body portion 11. The body portion 11 has a generationpart attaching portion 11 a for attaching a generation part constitutedby the rotor 4 and the stator portion 6. The generation part attachingportion 11 a is constituted by an open end face portion formed on theright side of the body portion 11 in FIG. 1 and an outer peripheralportion thereof, and a circumferential groove 11 b is formed in theouter peripheral portion. An O ring 8 is embedded in the groove 11 b.

Furthermore, a flange portion 52 of the cup-shaped member 5 is pushed toseal the O ring 8 in the groove 11 b and a cover member 9 is provided tointerpose the flange portion 52 of the cup-shaped member 5 together withthe generation part attaching portion 11 a in a state in which the outerperipheral end of the flange portion 52 is caused to abut on a convexportion 11 d formed in the body portion 11 (see the enlarged view ofFIG. 1). More specifically, the cup-shaped member 5 is pushed againstthe generation part attaching portion 11 a while crushing the O ring 8in the groove 11 b, and furthermore, the cover member 9 covers fromabove. When the outer peripheral end of the flange portion 52 of thecup-shaped member 5 is thus caused to abut on the inner peripheral partof the convex portion 11 d, the cup-shaped member 5 is positioned in theinner peripheral part of the stator portion 6. As shown in FIG. 2, fourscrews 10 are inserted in screw holes formed on four corners of thecover member 9 for screwing so that the cover portion 9 is fixed to thebody portion 11 of the casing 1. Consequently, the generation partattaching portion 11 a to be the open end face of the casing 1 is closedby the cup-shaped member 5.

The cup-shaped member 5 is formed of a non-magnetic stainless member,and has the flange portion 52, a cylindrical portion 51 and a bottomportion 53 formed through throttling. A bearing 15 for rotatablyreceiving one of ends of a shaft 7 supporting the hydraulic turbine 3and the rotor 4 is fitted in the bottom portion 53. The cup-shapedmember 5 serves to separate the stator portion 6 of the stepping motorfrom a fluid passing through the inside of the casing 1 and to preventthe fluid from flowing out of the casing 1.

The inlet path 12 and the outlet path 13 which are formed in the casing1 and a coupling path 14 for coupling them are provided in a part of afluid path of a Water Tap apparatus (as shown in FIG. 7) constituted bya faucet, a valve and the like, and a fluid entering the inlet path 12from a fluid source passes through the coupling path 14 and is thendischarged from the outlet path 13. The fluid serves to give therotating force to the hydraulic turbine 3 during the passage. Thisportion will be described below in detail. The other end of the shaft 7supporting the rotation of the hydraulic turbine 3 and the rotor 4 whichwill be described below is rotatably provided in the coupling path 14.One of ends of the shaft 7 is rotatably fitted in a hole 14 a for abearing which is formed in the coupling path 14 of the casing 1 and theother end side thereof is rotatably fitted in the bearing 15 having atip provided in the cup-shaped member 5 through the open end face.Consequently, the shaft 7 is held by cooperate the casing 1 with thecup-shaped member 5.

The nozzle ring 2 to be an injecting member acting as a part of thefluid path of the Water Tap apparatus and serving to throttle the flowof the passing fluid and to inject the fluid to a blade portion 31 (seeFIG. 4) of the hydraulic turbine 3 is fitted in the coupling path 14 ofthe casing 1 by pressure. The nozzle ring 2 has an cylindrical ringportion 21 and a flange portion 22 formed by bending one of open ends ofthe ring portion 21 in a peripheral direction. Two nozzles 23 areprovided in symmetrical positions by approximately 180 degrees in thering portion 21 as shown in FIG. 4 in such a manner that the two nozzles23 serve as injecting holes for throttling an inlet passage of the fluidentering the inlet path 12 and for injecting the fluid to the bladeportion 31 of the hydraulic turbine 3 disposed on the inside.

The hydraulic turbine 3, provided in the nozzle ring 2 to be a part ofthe fluid path, rotates with the passage of the fluid in a predeterminedflow. The hydraulic turbine 3 includes a cylindrical ring portion 32 andthe blade portion 31 having an outer peripheral tip portion connected toone of side end faces of the ring portion 32 and a central portioninserted and fixed to the shaft 7. The blade portion 31 is curvedcircularly to easily receive the pressure of the fluid from the nozzle23. For this reason, the fluid which enters the inlet path 12 and isthen throttled with the two nozzles 23 to have a pressure raised hits onthe blade portion 31 of the hydraulic turbine 3 vigorously and thehydraulic turbine 3 rotates around the shaft 7 by the hydroelectricthereof. The fluid hitting on the blade portion 31 is moved from thecoupling path 14 to the outlet path 13 through the open part of thehydraulic turbine 3 and the inner peripheral part of the ring portion32.

The rotor 4 is formed integrally through the hydraulic turbine 3 and acoupling shaft portion 35 and is provided coaxially with the hydraulicturbine 3. More specifically, the hydraulic turbine 3, the couplingshaft portion 35 and the rotor 4 are coupled in a direction of extensionof the shaft 7. Therefore, when the hydraulic turbine 3 rotates by thehydroelectric, the rotor 4 rotates around the shaft 7 integrally withthe hydraulic turbine 3. Four communicating holes 4 a communicating inthe direction of extension of the shaft 7 are formed on the couplingportion 35 and the rotor 4 at regular intervals in a circumferentialdirection. These communicating holes 4 a serve to give smooth rotationof the shaft 7 with respect to the bearing 15 by causing the fluid toflow into the right side of the rotor 4 in FIG. 1.

The rotor 4 serves as the rotor portion of the stepping motor in such amanner that the rotor 4 is coupled to the hydraulic turbine 3 rotatingtogether with the hydraulic turbine 3, and is constituted by a rotormagnet Mg having eight poles magnetized onto an outer peripheral surfacethereof. The outer peripheral surface is opposed to the stator portion 6of the stepping motor through the cylindrical portion 51 of thecup-shaped member 5. For this reason, in the case in which the rotor 4rotates together with the hydraulic turbine 3, it rotates relativelywith respect to the stator portion 6.

The stator portion 6 is constituted by two layers 6 a and 6 b which aresuperposed in an axial direction. Each of the layers 6 a and 6 bincludes an outer yoke (provided on the outside in a state ofsuperposition) 61, an outer pole tooth 61 a formed integrally with theouter yoke 61, an inner yoke (provided on the inside in the state ofsuperposition) 62, an inner pole tooth 62 a formed integrally with theinner yoke 62, and a coil 63 wound onto a coil bobbin. Start and endportions for winding the coil 63 are connected to a terminal 64,respectively.

The stator portion 6 thus constituted is fitted in the outside part ofthe cylindrical portion 51 of the cup-shaped member 5. Therefore, amagnetic flux flows between the pole teeth 61 a and 62 a of the statorportion 6 and the magnetized portion of the rotor 4. As described, whenthe rotor 4 rotates together with the hydraulic turbine 3, the flow ofthe magnetic flux is changed so that an induced voltage is generated onthe coil 63 in such a direction as to prevent the change in the flow.The induced voltage is taken out of the terminal 64. The induced voltagelead in such a form is converted into a direct current through acircuit, and the direct current is then rectified through apredetermined circuit (not shown) and is charged into a battery.

A specific flow for rotating the hydraulic turbine 3 will be describedbelow. The rotating force received by the hydraulic turbine 3 is set bythe flow and hydraulic pressure of the fluid. In other words, the fluidentering the inlet 12 is throttled by the nozzle 23 to some extent andis caused to vigorously hit on the blade portion 31 of the hydraulicturbine 3. Consequently, the hydraulic turbine 3 receives the rotatingforce from the fluid. As a matter of course, even if the hydraulicpressure is not raised by throttling the fluid path through the nozzle23, the hydraulic turbine 3 can rotate with a sufficient flow itself.However, if the fluid is caused to hit on the blade portion 31 of thehydraulic turbine 3 in a state in which the hydraulic pressure is raisedby the nozzle 23, it is possible to rotate the hydraulic turbine 3 witha smaller flow.

In the embodiment, the fluid path is throttled to raise the hydraulicpressure. However, if the hydraulic pressure is too raised, there isalso a possibility that the blade portion 31 of the hydraulic turbine 3,the nozzle ring 2 and other fluid paths for a fluid might be broken. Tothe contrary, if the hydraulic pressure is too low, the flow becomesinsufficient so that power generation cannot fully be carried out. Forthis reason, it is necessary to properly set the hydraulic pressure inrespect of the materials and thicknesses of the hydraulic turbine 3 andthe nozzle ring 2.

In addition to the shape of the blade portion 31 of the hydraulicturbine 3 and the total weight of the hydraulic turbine 3 (including theweight of the rotor 4), a detent torque generated between the rotor 4and the stator portion 6 acts as a resistance to be opposite to therotating force. The invention has a main object to reduce a detenttorque portion. In the embodiment, the stator portion 6 has a two-layerstructure and is skewed (each layer is shifted in a circumferentialdirection). Consequently, the pole tooth positions are shifted in thecircumferential direction, for example, and the detent torques generatedbetween the pole teeth and the magnetized portion of the rotor 4 to bethe rotor portion are cancelled from each other. Consequently, thedetent torque is reduced. Therefore, the detent torque between the rotor4 and the stator portion 6 which is generated during the rotation of thehydraulic turbine 3 does not effect as a very strong brake and thehydraulic turbine 3 can rotate smoothly with a small flow at a lowhydraulic pressure together with the rotor 4.

In the embodiment, thus, the stator portion 6 of the stepping motor hasthe two-layer structure and the shape and thickness of the blade portion31 are set to predetermined dimensions. Consequently, the hydraulicturbine 3 can rotate by utilizing a fluid flowing into the inlet path 12with 2.0 to 3.0 liters/minute.

In the embodiment, moreover, a minimum starting current amount at whicha generator starts to be rotated is set to approximately 1.2 to 1.5liters/minute. However, the amount of power generation is small.Furthermore, a voltage required for storage in a capacitor which is notshown is at least 5V or more in consideration of a conversion from AC toDC. Although a power can be generated with a slightly smaller flow than2.0 liters/minute in the embodiment, a flow of 2.0 liters/minute of moreis required for actually generating a power reliably.

On the other hand, the flow rate of 2.0 liters/minute is actually usedas a minimum flow rate for washing hands. From the foregoing, in theembodiment, a flow rate of 2.0 to 3.0 liters/minute is set to be a watersaving mode and a flow rate which is greater than 3.0 liters/minute isset to be a normal mode.

If the stator portion 6 has a single layer structure and other portionsare the same as those of the embodiment, the detent torque acts as thebrake more strongly than that in the embodiment described above. Morespecifically, the hydraulic turbine 3 can rotate with a flow rate whichis greater than 3 liters/minute.

Second Embodiment

Next, a small generator utilizing a brushless motor type according to asecond embodiment of the invention will be described with reference toFIGS. 5 and 6. In the description of the second embodiment, thedescription of the same structures as those in the first embodiment willbe omitted and the same components have the same reference numerals asthose in the first embodiment. FIG. 5 is a longitudinal sectional viewshowing a small generator according to the second embodiment of theinvention. Moreover, FIG. 6 is a side view showing the small generatorof FIG. 5 taken along an arrow VI in FIG. 5.

As shown in FIG. 5, the small generator utilizing a brushless motor typeaccording to the second embodiment has almost the same structure as thatin the first embodiment, and includes a casing 1, a nozzle ring 2provided in the casing 1, a hydraulic turbine 3 rotatably provided onthe inner peripheral side of the nozzle ring 2, a rotor 4 rotatesintegrally with the hydraulic turbine 3, a cup-shaped member 105 formedof stainless which is provided on the outer peripheral side of the rotor4, and a stator portion 106 of a brushless motor which is furtherprovided on the outside of the cup-shaped member 105.

A body portion 111 of the casing 1 has a generation part attachingportion 111 a for attaching a generation part constituted by the rotor 4and the stator portion 106. The generation part attaching portion 111 ais constituted by a concave portion 111 c having a hole in a centralpart formed on the right side of the body portion 111 in FIG. 1 and anouter peripheral portion thereof, and a circumferential groove 111 b isformed in the outer peripheral portion. An O ring 8 is embedded in thegroove 111 b.

Furthermore, a flange portion 152 formed in the outermost peripheralportion of the cup-shaped member 105 is pushed to seal the O ring 8 inthe groove 111 b and a cup-shaped member 90 is provided to interpose theouter peripheral end of the flange portion 152 together with thegeneration part attaching portion 111 a in a state in which the outerperipheral end of the flange portion 152 is caused to abut on a convexportion (which is not shown and has the same structure as that of thefirst embodiment) formed in the body portion 111. More specifically, thecup-shaped member 105 is pushed against the generation part attachingportion 111 a while crushing the O ring 8 in the groove 111 b, andfurthermore, the cup-shaped member 90 is provided from above. As shownin FIG. 6, four screws 10 are inserted in screw holes formed on fourcorners of the cup-shaped member 90 for screwing so that the cup-shapedmember 90 is fixed to the body portion 111 of the casing 1.Consequently, the generation part attaching portion 111 a to be the openend face of the casing 1 is closed by the cup-shaped member 105.

The cup-shaped member 105 is formed of a non-magnetic stainless member,and is provided with the flange portion 152 through throttling, an outercylindrical portion 155 connected to the flange portion 152, an innercylindrical portion 151 provided on the inside of the outer cylindricalportion, a coupled surface potion 156 coupling both cylindrical portions151 and 155, and a bottom portion 153. The cup-shaped member 105 thusconstituted is fitted in the concave portion 111 c of the generationpart attaching portion 111 a and is interposed and fixed between thecasing 1 and the cup-shaped member 90 as described above. A bearing 15for rotatably receiving one of ends of a shaft 7 supporting thehydraulic turbine 3 and the rotor 4 is fitted in the bottom portion 153.The cup-shaped member 105 serves to separate the stator portion 106 ofthe brushless motor from a fluid passing through the inside of thecasing 1 and to prevent the fluid from flowing out of the casing 1.

The nozzle ring 2 is press-fitted in the coupling path 14 of the casing1 in such a manner that the nozzle ring 2 acts to an injecting memberserving as a part of the fluid path of the Water Tap apparatus andeffecting to throttle the flow of the passing fluid and to inject thefluid to a blade portion 31 of the hydraulic turbine 3. The structure ofthe nozzle ring 2 is the same as that of the first embodiment. Moreover,the structures of the hydraulic turbine 3 provided on the inside of thenozzle ring 2 and the rotor 4 formed integrally with the hydraulicturbine 3 are also the same as those of the first embodiment.

The rotor 4 serves as the rotor portion of the brushless motor in such amanner that the rotor 4 coupled to the hydraulic turbine 3 rotatestogether with the hydraulic turbine 3, and is constituted by a rotormagnet Mg having two poles magnetized onto an outer peripheral surfacethereof. The outer peripheral surface is opposed to the stator portion106 of the brushless motor through the inner cylindrical portion 151 ofthe cup-shaped member 105. For this reason, in the case where the rotor4 rotates together with the hydraulic turbine 3, it rotates relativelywith respect to the stator portion 106.

The stator portion 6 is constituted by three coil portions 106 a, 106 band 106 c provided at regular intervals in a circumferential directionas shown in FIG. 6. Each of the coil portions 106 a, 106 b and 106 cincludes a stator core 161 and a coil 163 wound onto the stator core161. Start and end portions for winding the coil 163 are connected to aterminal 164, respectively.

The stator portion 106 thus constituted is fitted in a portion betweenthe inner cylindrical portion 151 of the cup-shaped member 105 and theouter cylindrical portion 155. For this reason, a magnetic flux flowsbetween an inner opposed surface 161 a of each yoke member 161 to be apole of the stator portion 106 and the magnetized portion of the rotor4. As described above, when the rotor 4 rotates together with thehydraulic turbine 3, the flow of the magnetic flux is changed so that aninduced voltage is generated on the coil 163 in such a direction as toprevent the change in the flow. The induced voltage is taken out of theterminal 164.

The induced voltage taken out in such a form is converted into a directcurrent through a circuit. An AC voltage induced by the generation parthaving an output coil to be a three-phase Y connection is rectifiedthrough a three-phase bridge circuit (not shown) having six diodes andone smoothing capacitor and is converted into a direct current to becharged into a battery.

The stator portion 106 is constituted by the three coil portions 106 a,106 b and 106 c as described above and has three poles. On the otherhand, the rotor 4 opposed to the stator portion 6 is two-pole magnetizedas described above. More specifically, in the embodiment, the brushlessmotor type is used and the number of poles magnetized onto the rotor(rotor portion) 4 and the number of coil portions (the number of poles)of the stator portion 106 have a relationship of 2-3. For this reason, adetent torque generated between the stator portion 106 and the stator 4is not so great as that in the conventional single layer stepping motortype. Consequently, the detent torque between the rotor 4 and the statorportion 106 which is generated during the rotation of the hydraulicturbine 3 does not act as a very great brake and the hydraulic turbine 3can rotate smoothly with a small flow at a low hydraulic pressuretogether with the rotor 4.

The relationship between the number of poles magnetized onto the rotor(rotor portion) 4 and the number of coil portions (the number of poles)of the stator portion 106 may be 4-3 or 4-6 in place of 2-3 in theembodiment, for example. Also in the second embodiment in which the mainpart of the generator is thus constituted by the brushless motor type,the hydraulic turbine 3 can rotate by utilizing a fluid flowing into aninlet path 12 with 2.0 to 3.0 liters/minute in the same manner as in thefirst embodiment.

If the structure of the generator has a stepping motor type and thestator portion has a single layer structure (the stator portion has thetwo-layer structure in the first embodiment), the detent torque is greatand acts as a brake as described above. More specifically, the hydraulicturbine 3 can rotate with a flow of 3 liters/minute or more. Asdescribed above, it is possible to generate a power in a small amount ofwater by causing the structure of the main part of the generator to havethe brushless motor type.

The small generator according to each of the embodiments can generate apower by utilizing a small flow of 2.0 to 3.0 liters/minute. Inaddition, also in the case in which the flow is more than 3.0liters/minute, it is a matter of course that the power can be generated.In addition, the rotor 4 rotates smoothly without an influence of thedetent torque. Therefore, a generation output per rotation speed ishigher than that in the conventional art.

There are such effects. In a Water Tap apparatus having the smallgenerator according to each of the embodiments attached thereto,therefore, a valve opening degree is controlled to include at least twomode specifications such as a water saving mode in which a flow of thefluid to flow to the fluid path is set to be smaller than usual and anormal mode in which the flow is normal, and the flow in the watersaving mode may be set to 2.0 to 3.0 liters/minute as described above.Thus, the power can be generated in the water saving mode and thegeneration output having a high efficiency can be obtained in the normalmode.

In each of the embodiments, as described above, it is possible to morereduce the detent torque than that in the conventional stepping motortype having a single layer structure. Therefore, a hole diameter of thenozzle 23 may be increased to reduce a hydraulic pressure to be appliedto the hydraulic turbine 3, for example, and it is also possible tofurther reduce a possibility that the nozzle ring 2 and the hydraulicturbine 3 might be broken due to the hydraulic pressure. In that case,the lowest flow with which the hydraulic turbine 3 can rotate isslightly raised corresponding to the increase in the hole diameter ofthe nozzle 23 and the reduction in the hydraulic pressure. If the flowis approximately 2.5 liters/minute, for example, much higher performancecan be obtained as compared with that in the conventional art.

Next, a water tap apparatus employing the small generator of the presentinvention described above will be described below more in detail.

FIGS. 7(a) and (b) show sectional views of the water tap apparatuscontaining the small generator of the present invention. FIG. 8 is ablock diagram of relationship among a small generator, a capacitor and acontroller.

In FIGS. 7(a) and (b), a water tap 1000 contains a spout and a humanbody detecting sensor 1001 for detecting a hand. The following parts areprovided in the water tap 1000, that is, a solenoid valve 1002 opens andcloses water flow, a small generator 1005 is shown in FIG. 1 or 5, acontroller 1003 for controlling the opening/closing of the solenoidvalve 1002 includes a DC converter (not shown) for converting an inducedvoltage to a direct current and a rectifier circuit for rectifying thedirect current, and a capacitor 1004 storages a rectified current.

Next, the water tap 1000 operation will be described hereinbelow. When ahuman hand is detected by the sensor 1001, a signal send from the sensor1001 to the controller 1003. The controller 1003 outputs the open signalto the solenoid valve 1002. Then, the solenoid valve open to spout awater. The water flows in the tube located in the water tap to reach thesmall generator 1005. In the small generator 1005, the water enteringinto the inlet path is throttled by the nozzle or the like to increasethe hydraulic pressure. Then water hits on the blade portion of thehydraulic turbine to generate an induced voltage. The induced voltage isconverted to the direct current by the DC converter (not shown) andrectified by passing through the rectifier circuit (not shown) tostorage the capacitor (not shown).

Then, the current storaged in the capacitor (not shown) is applied tothe controller 1002.

On the other hand, when the human hand is not detected, the sensor 1001recognizes the condition to output a signal to the controller 1002 toclose the solenoid valve 1003.

The water tap 1000 operation is not limited by this embodiment describedabove. The following operation could be employed such that afterspouting a predetermined amount of the water, the water flow isautomatically stopped.

In the small generator according to the invention, the rotor coupled tothe hydraulic turbine which rotates through the passage of the fluidacts as the rotor portion opposed to the stator portion having multiplelayers in the stepping motor including the stator portion. Therefore,each layer acts to cancel a detent torque between the stator portion andthe rotor so that the detent torque can be reduced. As a result, thehydraulic turbine can rotate with a low flow at a low hydraulicpressure.

In the small generator according to another invention, moreover, therotor coupled to the hydraulic turbine which rotates through the passageof the fluid serves as the rotor portion opposed to the stator portionof the brushless motor including the stator portion having a pluralityof coil portions. Consequently, it is possible to reduce the detenttorque. As a result, it is possible to rotate the hydraulic turbine witha small flow at a low hydraulic pressure.

Furthermore, the Water Tap apparatus according to the invention has atleast two modes of a water saving mode and a normal mode by controllingthe valve opening degree, and is provided with the small generator inthe fluid path. In the Water Tap apparatus according to the invention,thus, the small generator having a detent torque reduced is provided inthe fluid path so that the power can be generated with a small flow at alow hydraulic pressure. Consequently, if the hydraulic pressure of thefluid to be supplied to the hydraulic turbine is set to be low, it ispossible to reduce a possibility that a member might be damaged at ahigh hydraulic pressure in the normal mode and a power can fully begenerated also in the water saving mode.

1. A small generator comprising: a hydraulic turbine, provided in afluid path, rotating by passing a fluid in a predetermined flow rate; arotator, coupled to the hydraulic turbine, rotating together with thehydraulic turbine, the rotator acting as a rotor portion opposed to astator portion having multiple layers in a stepping motor including thestator portion, wherein the rotor portion rotates relatively withrespect to the stator portion by with passing the fluid to generate apower.
 2. The small generator according to claim 1, wherein a detenttorque generated between the stator portion and the rotor is set to becanceled by arranging the layers each other.
 3. A small generatorcomprising: a hydraulic turbine, provided in a fluid path, rotating bypassing a fluid in a predetermined flow rate; a rotator, coupled to thehydraulic turbine, rotating together with the hydraulic turbine, therotator acting as a rotor portion opposed to a stator portion having aplurality of coil portions in a brushless motor including the statorportion, wherein the rotor portion relatively rotates with respect tothe stator portion by passing the fluid to generate a power.
 4. Thesmall generator according to claim 3, wherein a relationship between thenumber of poles magnetized onto the rotor portion and the number of coilportions of the stator portion is set to one of 2-3, 4-3 and 4-6.
 5. Thesmall generator according to claim 1, further comprising: an injectingmember including an injecting hole acting as a part of the fluid pathand serving to throttle a flow for a passage to inject a fluid onto ablade portion of the hydraulic turbine.
 6. A Water Tap apparatuscomprising: a valve opening degree controlled to include at least twomodes of a water saving mode in which a flow of a fluid to flow to afluid path and a normal mode for a normal and a small generatoraccording to claim 1 arranged on the fluid.
 7. The Water Tap apparatusaccording to claim 6, wherein the flow in the water saving mode is setto 2.0 liters/minute to 3.0 liters/minute.
 8. The small generatoraccording to claim 3, further comprising: an injecting member includingan injecting hole acting as a part of the fluid path and serving tothrottle a flow for a passage to inject a fluid onto a blade portion ofthe hydraulic turbine.
 9. A Water Tap apparatus comprising: a valveopening degree is controlled to include at least two modes of a watersaving mode in which a flow of a fluid to flow to a fluid path and anormal mode for a normal flow; and a small generator according to claim3 arranged on the fluid.
 10. The Water Tap apparatus according to claim9, wherein the flow in the water saving mode is set to 2.0 to 3.0liter/minute.